Labour is today proposing a motion in favour of a mansions tax. It reads as follows:

"That this House believes that a mansion tax on properties worth over £2m, to fund a tax cut for millions of people on middle and low incomes, should be part of a fair tax system; and calls on the government to bring forward proposals for such a tax at the earliest opportunity."

Ed Miliband had hoped that the Lib Dems might back the motion – a mansions tax was, after all, Vince Cable's policy before it was Ed Balls'. After Cable had appeared to flirt with supporting the Labour motion the Coalition partners have agreed an alternative motion that captures the differing Tory and Lib Dem views on the taxation of high value properties:

"Line 1, leave out from ‘House’ to end and add ‘notes that this coalition government has cut income tax for 25 million people, taking over 2.2 million low income individuals out of income tax altogether, while at the same time increasing taxes on the wealthy, including raising stamp duty on expensive properties and restricting tax reliefs; further notes that both parts of the coalition continue to support tax cuts for people on low and middle incomes; notes that the part of the coalition led by the deputy prime minister also advocates a mansion tax on properties worth more than £2m, as set out in his party’s manifesto, and the part of the coalition led by the prime minister does not advocate a mansion tax; and further notes that the top rate of income tax will be higher under this government than under any year of the previous administration and that the rich are now paying a higher percentage of income tax than at any time under the previous administration, demonstrating that it presided over an unfair tax system where the rich paid less and the poor paid more in tax than now, meaning nobody will trust the opposition’s promises on tax fairness.’."

Conservative HQ meanwhile senses a political opportunity and has unveiled leaflets, warning homeowners that Labour wants to "snoop" around their houses, looking to revalue them and increase the tax burden on them. Coalition etiquette means that the leaflets don't also talk about a Lib Dem homes tax but the posters could easily be adapted to do just that.

I'm not sure everyone will get the "little brother" joke! Here's the other side of the Tory leaflet…

I support higher taxation of high value properties (via extra council tax bands) and I'd use the proceeds to cut the tax burden on the low-paid… but I see the politics of the Tory tactic.

Tory HQ is suggesting that Ed Miliband would have to tax properties worth £415,000 or more to reintroduce the 10p tax band in the way Labour has claimed.